Nanofat grafting: basic research and clinical applications. Plast Reconstr Surg. 2013;132:1017-1026. [PMID: 23783059 DOI: 10.1097/prs.0b013e31829fe1b0]

Increased Fat Graft Survival by Promoting Adipocyte Dedifferentiation

BACKGROUND

Some adipocytes undergo dedifferentiation after fat transplantation, and this may affect the survival of fat grafts. However, this effect has not been adequately studied.

OBJECTIVES

This study aimed to clarify the effect of promoting the dedifferentiation of mature adipocytes on the survival of fat grafts.

METHODS

Mature adipocytes and adipose stem cells (ASCs) were treated with OSI-906 (a specific inhibitor of insulin receptor and insulin-like growth factor-1 receptor) in vitro, and then the dedifferentiation of mature adipocytes and the proliferation of ASCs were evaluated. In the in vivo experiment, human lipoaspirates mixed with phosphate-buffered saline (Group A) or OSI-906 (Group B) were compared in nude mice. Grafts were harvested at 2, 8, and 12 weeks, and volume retention rate, histologic, and immunohistochemical analyses were conducted.

RESULTS

OSI-906 can promote the dedifferentiation of mature adipocytes and inhibit the proliferation of ASCs. At 12 weeks, Group B showed a better volume retention rate (mean [standard deviation, SD], 62.3% [7.61%]) than group A (47.75% [6.11%]) (P < .05). Moreover, viable adipocytes and vascularization showed greater improvement in Group B than in Group A.

CONCLUSIONS

This study suggests that promoting the dedifferentiation of mature adipocytes can improve the survival rate and quality of fat grafts.

The LipoDerm Method for Regeneration and Reconstruction in Plastic Surgery: A Technical Experimental Ex Vivo Note

The combination of adipose-derived stem cells (ASCs) and dermal scaffolds has been shown to be an approach with high potential in soft tissue reconstruction. The addition of dermal templates to skin grafts can increase graft survival through angiogenesis, improve regeneration and healing time, and enhance the overall appearance. However, it remains unknown whether the addition of nanofat-containing ASCs to this construct could effectively facilitate the creation of a multi-layer biological regenerative graft, which could possibly be used for soft tissue reconstruction in the future in a single operation. Initially, microfat was harvested using Coleman's technique, then isolated through the strict protocol using Tonnard's technique. Finally, centrifugation, emulsification, and filtration were conducted to seed the filtered nanofat-containing ASCs onto Matriderm for sterile ex vivo cellular enrichment. After seeding, a resazurin-based reagent was added, and the construct was visualized using two-photon microscopy. Within 1 h of incubation, viable ASCs were detected and attached to the top layer of the scaffold. This experimental ex vivo note opens more dimensions and horizons towards the combination of ASCs and collagen-elastin matrices (i.e., dermal scaffolds) as an effective approach in soft tissue regeneration. The proposed multi-layered structure containing nanofat and dermal template (Lipoderm) may be used, in the future, as a biological regenerative graft for wound defect reconstruction and regeneration in a single operation and can also be combined with skin grafts. Such protocols may optimize the skin graft results by creating a multi-layer soft tissue reconstruction template, leading to more optimal regeneration and aesthetic outcomes.

Fat Injection as a Valuable Tool for Lower Eyelid Retraction Management: A Retrospective, Observational, Single Blind and Case-Control Study

BACKGROUND

The aim of this study was to evaluate the use of autologous fat graft injection to correct lower eyelid position METHODS: A retrospective, observational, single blind, case-control study was carried out on 94 patients, presenting with lower eyelid retraction in 159 eyes. In the sub-population with monolateral eyelid retraction, the not affected site has been considered as a control and compared with the outcomes recorded after treatment of the contralateral side Follow-up at 12 months was performed with a subjective assessment carried out by a questionnaire administered to patients while objective result assessment was performed 12 months after surgery by two independent blind examiners.

RESULTS

The eyelid upward reposition has improved one year after fat grafting in both bilateral (1,52 mm) and unilateral (1,7 mm) population: the latter allowed to statistically validate (P<0.05) the result with respect to the not affected site.

CONCLUSIONS

This is the first paper that highlights the outcomes of sole fat injection in the treatment of lower eyelid retraction: blind objective evaluation of surgical outcomes along with a patient assessment of both functional and aesthetic improvement one year after surgery confirm its efficacy and reliability along with the first case/control outcome evaluation of the technique carried on in the sub-population of 29 patients affected by unilateral lower eyelid retraction that validate the average improvement of the retracted eyelid one year after fat grafting as statistically significant. Nevertheless, longer follow-up periods and a larger sample size are needed to thoroughly confirm surgical outcomes and statistical results.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

A Bibliometric and Visualization Analysis on the Research of Fat Grafting from 1945 to 2021

BACKGROUND

It is very important to generate a comprehensive assessment of the fat grafting field due to the rapid growth of scientific literature. The current study aimed to use bibliometric analysis to evaluate fat grafting research qualitatively and quantitatively and determine the research hotspots and trends in this field.

METHODS

Publications on fat grafting research were extracted from the Web of Science core collection database. VOSviewer 1.6.18 was applied to perform the bibliometric analysis of these articles.

RESULTS

A total of 2558 studies published by 594 different journals authored by 9097 researchers were contained in this study. In the co-authorship analysis, the bulk of the retrieved studies was conducted by the USA, followed by China, Italy and Japan, while the most productive institution, journal and author were Chinese Academy of Medicine Sciences, Plastic and Reconstruction Surgery and Klinger M, respectively. In the co-cited analysis, the most top cited author, journal, organization and country were Coleman Sr, Plastic and Reconstruction Surgery, New York University and the USA, respectively. The map of keywords occurrence revealed the most active research aspects were focused on "surgery," "cell," "breast reconstruction" and "survival" and the time overlay mapping showed that the most active research hotspots were "breast reconstruction" and "retention".

CONCLUSIONS

The research hotspots include the following four aspects: aesthetic surgeries, cell-assisted lipotransfer, breast reconstruction and grafted fat survival. Breast fat grafting and volume retention may be trends in the future. We are willing to provide more beneficial data to contribute valuable research for the fat grafting through this study.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Autologous Shuffling Lipo-Aspirated Fat Combined Mechanical Stretch in Revision Rhinoplasty for Severe Contractures in Asian Patients

BACKGROUND

A severely contracted nose is a common occurrence. Intraoperative expansion is not sufficient to soften the severely constricted nasal envelope, which poses challenges in revision rhinoplasty. In recent years, adjuvant therapies, including nasal fat grafting and cell component injection, are applied before revision rhinoplasty to soften the nasal envelope. Herein, autologous shuffling lipo-aspirated fat and manual mechanical stretch were combined as adjuvant therapy before revision rhinoplasty.

METHODS

A total of 24 patients with severe nasal contracture were included in this study. Of these, 8 received autologous shuffling lipo-aspirated fat and manual mechanical stretch before revision rhinoplasty (comprehensive therapy), 8 underwent mechanical stretch and revision rhinoplasty, and 8 patients underwent only revision rhinoplasty. The objective and subjective outcome assessment was processed in the follow-up period of 6 months. Nasal length, nasal tip projection, nasofrontal angle, and nasolabial angle were measured, and potential complications were assessed.

RESULTS

All 24 patients underwent a successful revision rhinoplasty. In the comprehensive therapy group, no patient had postoperative wound infection and defect of the nasal column mucous. The comprehensive treatment group had the most significant improvement in nasal length and nasal tip projection, and the nasolabial angle was the closest to 90°, which indicated the most effective nasal revision and aesthetic contour.

CONCLUSIONS

The adjuvant therapy combines autologous shuffling lipo-aspirated fat and manual mechanical stretch before revision rhinoplasty could effectively improve the surgical outcome and decrease the postoperative complications regarding severe nasal contractures.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Adipose Tissue and Adipose-Tissue-Derived Cell Therapies for the Treatment of the Face and Hands of Patients Suffering from Systemic Sclerosis

Adipose tissue is recognized as a valuable source of cells with angiogenic, immunomodulatory, reparative and antifibrotic properties and emerged as a therapeutic alternative for the regeneration and repair of damaged tissues. The use of adipose-tissue-based therapy is expanding in autoimmune diseases, particularly in Systemic Sclerosis (SSc), a disease in which hands and face are severely affected, leading to disability and a decrease in quality of life. Combining the advantage of an abundant supply of fat tissue and a high abundance of stem/stromal cells, fat grafting and adipose tissue-derived cell-based therapies are attractive therapeutic options in SSc. This review aims to synthesize the evidence to determine the effects of the use of these biological products for face and hands treatment in the context of SSc. This highlights several points: the need to use relevant effectiveness criteria taking into account the clinical heterogeneity of SSc in order to facilitate assessment and comparison of innovative therapies; second, it reveals some impacts of the disease on fat-grafting success; third, an important heterogeneity was noticed regarding the manufacturing of the adipose-derived products and lastly, it shows a lack of robust evidence from controlled trials comparing adipose-derived products with standard care.

Micro-fragmented and nanofat adipose tissue derivatives: In vitro qualitative and quantitative analysis

Introduction: Adipose tissue is widely exploited in regenerative medicine thanks to its trophic properties, mainly based on the presence of adipose-derived stromal cells. Numerous devices have been developed to promote its clinical use, leading to the introduction of one-step surgical procedures to obtain minimally manipulated adipose tissue derivatives. However, only a few studies compared their biological properties. This study aimed to characterize micro-fragmented (MAT) and nanofat adipose tissue (NAT) obtained with two different techniques. Methods: MAT, NAT and unprocessed lipoaspirate were collected from surgical specimens. RNA extraction and collagenase isolation of stromal vascular fraction (SVF) were performed. Tissue sections were analysed by histological and immunohistochemical (collagen type I, CD31, CD34 and PCNA) staining to assess tissue morphology and cell content. qPCR was performed to evaluate the expression of stemness-related (SOX2, NANOG and OCT3/4), extracellular matrix (COL1A1) and inflammatory genes (IL1β, IL6 and iNOS). Furthermore, multilineage differentiation was assessed following culture in adipogenic and osteogenic media and staining with Oil Red O and Alizarin red. ASC immunophenotype was assessed by flow cytometric analysis of CD90, CD105, CD73 and CD45. Results: Histological and immunohistochemical results showed an increased amount of stroma and a reduction of adipocytes in MAT and NAT, with the latter displaying the highest content of collagen type I, CD31, CD34 and PCNA. From LA to MAT and NAT, an increasing expression of NANOG, SOX2, OCT3/4, COL1A1 and IL6 was noted, while no significant differences in terms of IL1β and iNOS emerged. No statistically significant differences were noted between NAT and SVF in terms of stemness-related genes, while the latter demonstrated a significantly higher expression of stress-related markers. SVF cells derived from all three samples (LA, MAT, and NAT) showed a similar ASC immunoprofile as well as osteogenic and adipogenic differentiation. Discussion: Our results showed that both MAT and NAT techniques allowed the rapid isolation of ASC-rich grafts with a high anabolic and proliferative potential. However, NAT showed the highest levels of extracellular matrix content, replicating cells, and stemness gene expression. These results may provide precious clues for the use of adipose tissue derivatives in the clinical setting.

Fat Juice: A Novel Approach on the Usage and Preparation of Adipose Tissue By-Products

BACKGROUND

Adipose tissue is considered to be naturally rich in a range of bioactive substances that may be extracted directly for therapeutic use without the need for cell isolation or culture.

OBJECTIVES

The aim of this study was to introduce a novel approach that utilizes stromal vascular fraction in conjunction with fat extract, termed "fat juice," and to perform a comprehensive biochemical analysis in relation to the potential clinical relevance of this new combination.

METHODS

A total of 11 samples of fat juice from the abdominal lipoaspirate were extracted from 11 healthy patients and analyzed in terms of the quantity and viability of stem cells, the presence and quantification of connective tissue fibers on histopathologic examination, and the levels of interleukin-6, mannose receptor C type 1, and vascular endothelial growth factor measured by enzyme-linked immunosorbent assay.

RESULTS

Total stem cell amounts ranged from 0.14 × 105 to 1.31 × 105, and cell viability rates varied between 20% and 67.9%. Interleukin-6 protein and vascular endothelial growth factor expressions were highest in Sample 3, while staining intensity was highest in Sample 4. For collagen I, collagen III, and elastin, the highest expressions were observed in Samples 4 and 8, in Sample 3, and in Samples 2 and 4, respectively.

CONCLUSIONS

Fat juice provides an easy-to-inject concentration of adipocyte/preadipocytes, red blood cells, adipose-derived stem cells, endothelial-derived cells, and cell residues. Prepared through an easy isolation process enabling abundant availability, fat juice seems to be an effective skin quality enhancer with potential for widespread use in the fields of plastic surgery, dermatology, and aesthetic/regenerative medicine.

Mechanism of action and therapeutic effects of oxidative stress and stem cell-based materials in skin aging: Current evidence and future perspectives

Aging is associated with multiple degenerative diseases, including atherosclerosis, osteoporosis, and Alzheimer's disease. As the most intuitive manifestation of aging, skin aging has received the most significant attention. Skin aging results from various intrinsic and extrinsic factors. Aged skin is characterized by wrinkles, laxity, elastosis, telangiectasia, and aberrant pigmentation. The underlying mechanism is complex and may involve cellular senescence, DNA damage, oxidative stress (OS), inflammation, and genetic mutations, among other factors. Among them, OS plays an important role in skin aging, and multiple antioxidants (e.g., vitamin C, glutathione, and melatonin) are considered to promote skin rejuvenation. In addition, stem cells that exhibit self-replication, multi-directional differentiation, and a strong paracrine function can exert anti-aging effects by inhibiting OS. With the further development of stem cell technology, treatments related to OS mitigation and involving stem cell use may have a promising future in anti-skin aging therapy.

Anatomical Study of the Penile Suspensory System: A Surgical Application to Micropenis

Penile enlargement surgery is the second most desired cosmetic procedure in men worldwide. The mainstay of penile lengthening procedures is a partial release of the penile suspensory ligament system. Concerns regarding erect penis stability after this procedure have been raised by the surgical community. This study describes the anatomical features of the penile suspensory ligament system and explores the stability mechanisms of the penis.

Methods

This study is subdivided in two parts: an anatomical analysis and a clinical analysis. The anatomical part consists of a dissection of eight male cadavers to describe the anatomy and test the stability after sectioning successively the suspensory ligaments. The clinical part consists of an analysis of 30 patients with micropenis operated on for penile lengthening by a penile suspensory ligament release and lipofilling.

Results

The suspensory apparatus consists of four distinct ligamentous structures: fundiform, suspensory, dense vertical, and arcuate ligaments. These different structures are lax superficially but become firm and tense posteriorly. The section of the fundiform and suspensory ligaments did not destabilize the penis.

Conclusion

Penile lengthening by way of cautious suspensory ligament release can be performed without erection instability.

Highly Pluripotent Adipose-Derived Stem Cell-Enriched Nanofat: A Novel Translational System in Stem Cell Therapy

Fat graft is widely used in plastic and reconstructive surgery. The size of the injectable product, the unpredictable fat resorption rates, and subsequent adverse effects make it tricky to inject untreated fat into the dermal layer. Mechanical emulsification of fat tissue, which Tonnard introduced, solves these problems, and the product obtained was called nanofat. Nanofat is widely used in clinical and aesthetic settings to treat facial compartments, hypertrophic and atrophic scars, wrinkle attenuation, skin rejuvenation, and alopecia. Several studies demonstrate that the tissue regeneration effects of nanofat are attributable to its rich content of adipose-derived stem cells. This study aimed to characterize Hy-Tissue Nanofat product by investigating morphology, cellular yield, adipose-derived stem cell (ASC) proliferation rate and clonogenic capability, immunophenotyping, and differential potential. The percentage of SEEA3 and CD105 expression was also analyzed to establish the presence of multilineage-differentiating stress-enduring (MUSE) cell. Our results showed that the Hy-Tissue Nanofat kit could isolate 3.74 × 10⁴ ± 1.31 × 10⁴ proliferative nucleated cells for milliliter of the treated fat. Nanofat-derived ASC can grow in colonies and show high differentiation capacity into adipocytes, osteocytes, and chondrocytes. Moreover, immunophenotyping analysis revealed the expression of MUSE cell antigen, making this nanofat enriched of pluripotent stem cell, increasing its potential in regenerative medicine. The unique characteristics of MUSE cells give a simple, feasible strategy for treating a variety of diseases.

Fluidic Device System for Mechanical Processing and Filtering of Human Lipoaspirate Enhances Recovery of Mesenchymal Stem Cells

BACKGROUND

Adipose tissue is an easily accessible source of stem and progenitor cells that offers exciting promise as an injectable autologous therapeutic for regenerative applications. Mechanical processing is preferred over enzymatic digestion, and the most common method involves shuffling lipoaspirate between syringes and filtering to produce nanofat. Although nanofat has shown exciting clinical results, the authors hypothesized that new device designs could enhance recovery of stem/progenitor cells through optimization of fluid dynamics principles, integration, and automation.

METHODS

The authors designed and fabricated the emulsification and micronization device (EMD) and the filtration device (FD) to replace the manual nanofat procedures. Using human lipoaspirate samples, the EMD and the FD were optimized and compared to traditional nanofat using ex vivo measurements of cell number, viability, and percentage of mesenchymal stem cells and endothelial progenitor cells.

RESULTS

The EMD produced results statistically similar to nanofat, and these findings were confirmed for a cohort of diabetic patients. Combining the FD with the EMD was superior to manually filtered nanofat in terms of both recovered cell percentages (>1.5-fold) and numbers (two- to three-fold). Differences were statistically significant for total mesenchymal stem cells and a DPP4 + /CD55 + subpopulation linked to improved wound healing in diabetes.

CONCLUSIONS

The new EMD and the FD improved mechanical processing of human lipoaspirate in terms of mesenchymal stem cell enrichment and number compared to traditional nanofat. Future work will seek to investigate the wound healing response both in vitro and in vivo, and to refine the technology for automated operation within clinical settings.

CLINICAL RELEVANCE STATEMENT

The new devices improved mechanical processing of human lipoaspirate in terms of stem cell enrichment and number compared to traditional methods. Future work will seek to validate wound healing response and refine the technology for automated operation within clinical settings.

Therapeutic potential of adipose tissue-derivatives in modern dermatology

Stem cell-mediated therapies in combination with biomaterial and growth factor-based approaches in regenerative medicine are rapidly evolving with increasing application beyond the dermatologic field. Adipose-derived stem cells (ADSCs) are the more frequently used adult stem cells due to their abundance and easy access. In the case of volumetric defects, adipose tissue can take the shape of defects, restoring the volume and enhancing the regeneration of receiving tissue. When regenerative purposes prevail on volume restoration, the stromal vascular fraction (SVF) rich in staminal cells, purified mesenchymal stem cells (MSCs) or their cell-free derivatives grafting are favoured. The therapeutic efficacy of acellular approaches is explained by the fact that a significant part of the natural propensity of stem cells to repair damaged tissue is ascribable to their secretory activity that combines mitogenic factors, cytokines, chemokines and extracellular matrix components. Therefore, the secretome's ability to modulate multiple targets simultaneously demonstrated preclinical and clinical efficacy in reversing pathological mechanisms of complex conditions such atopic dermatitis (AD), vitiligo, psoriasis, acne and Lichen sclerosus (LS), non-resolving wounds and alopecia. This review analysing both in vivo and in vitro models gives an overview of the clinical relevance of adipose tissue-derivatives such as autologous fat graft, stromal vascular fraction, purified stem cells and secretome for skin disorders application. Finally, we highlighted the major disease-specific limitations and the future perspective in this field.

Autologous Adipose-Derived Tissue Stromal Vascular Fraction (AD-tSVF) for Knee Osteoarthritis

Adipose tissue contains adult mesenchymal stem cells that may modulate the metabolism when applied to other tissues. Stromal vascular fraction (SVF) can be isolated from adipose tissue mechanically and/or enzymatically. SVF was recently used to decrease the pain and improve the function of knee osteoarthritis (OA) patients. Primary and/or secondary OA causes inflammation and degeneration in joints, and regenerative approaches that may modify the natural course of the disease are limited. SVF may modulate inflammation and initiate regeneration in joint tissues by initiating a paracrine effect. Chemokines released from SVF may slow down degeneration and stimulate regeneration in joints. In this review, we overviewed articular joint cartilage structures and functions, OA, and macro-, micro-, and nano-fat isolation techniques. Mechanic and enzymatic SVF processing techniques were summarized. Clinical outcomes of adipose tissue derived tissue SVF (AD-tSVF) were evaluated. Medical devices that can mechanically isolate AD-tSVF were listed, and publications referring to such devices were summarized. Recent review manuscripts were also systematically evaluated and included. Transferring adipose tissues and cells has its roots in plastic, reconstructive, and aesthetic surgery. Micro- and nano-fat is also transferred to other organs and tissues to stimulate regeneration as it contains regenerative cells. Minimal manipulation of the adipose tissue is recently preferred to isolate the regenerative cells without disrupting them from their natural environment. The number of patients in the follow-up studies are recently increasing. The duration of follow up is also increasing with favorable outcomes from the short- to mid-term. There are however variations for mean age and the severity of knee OA patients between studies. Positive outcomes are related to the higher number of cells in the AD-tSVF. Repetition of injections and concomitant treatments such as combining the AD-tSVF with platelet rich plasma or hyaluronan are not solidified. Good results were obtained when combined with arthroscopic debridement and micro- or nano-fracture techniques for small-sized cartilage defects. The optimum pressure applied to the tissues and cells during filtration and purification of the AD-tSVF is not specified yet. Quantitative monitoring of articular joint cartilage regeneration by ultrasound, MR, and synovial fluid analysis as well as with second-look arthroscopy could improve our current knowledge on AD-tSVF treatment in knee OA. AD-tSVF isolation techniques and technologies have the potential to improve knee OA treatment. The duration of centrifugation, filtration, washing, and purification should however be standardized. Using gravity-only for isolation and filtration could be a reasonable approach to avoid possible complications of other methodologies.

Single session of combined microfat and subcision in the treatment of Grade 4 atrophic acne scars

BACKGROUND

Severe atrophic acne scars (AAS) remain the "Achilles's heel" of AAS treatment. The combination of microfat and subcision treatment is a potential solution for severe AAS.

AIMS

This study aimed to evaluate the efficacy and safety of combined microfat and subcision treatment for severe (Grade 4) AAS.

METHODS

Data of patients with Grade 4 AAS who underwent combined microfat and subcision treatment between September 2016 and December 2020 were reviewed. Post-treatment evaluation was performed at least 3 months postoperatively. The severity of AAS was graded based on Goodman's qualitative classification. The volume of concavities was measured using an Antera 3D camera. Complications were documented.

RESULTS

A total of 42 patients received a single treatment session. Excellent response was observed in 5 (11.9%) patients, very good in 13 (31.0%), good in 22 (52.4%), and poor response in 2 (4.7%). The average reduction of the total volume of concavities was 28.0%. The most common minor side effects were mild swelling and bruising. No major complications were observed.

CONCLUSIONS

Combined microfat and subcision treatment is a safe and effective treatment for severe AAS. The approach will be a significant treatment for severe AAS.

An Optimized Method for Adipose Stromal Vascular Fraction Isolation and its Application in Fat Grafting

BACKGROUND

The stromal vascular fraction (SVF) derived from adipose tissue contains heterogeneous cell populations and has enormous potential for clinical therapy. There are two main methods for SVF isolation: enzymatic isolation and mechanical isolation, both of which have shortcomings. In this study, optimized conditions for the isolation of high-quality SVF were established, and applications in fat grafting were evaluated.

METHODS

Adipose tissue was chopped into small pieces and then ground into an erosive shape using a syringe. The pieces were digested with 0.15% type II collagenase for 35 min at 37 °C. After centrifugation, the pellets were resuspended in DMEM and passed through a 100-μm strainer. The filtered cells were analyzed by flow cytometry. The fat graft was enriched with isolated SVF and subcutaneously transplanted into nude mice. Three weeks after transplantation, grafts were isolated, and H&E staining, immunocytochemistry, and western blotting were conducted.

RESULTS

The harvested SVF cells reached > 2 × 106/ml of adipose tissue within 90 min of operation. The number of CD34+ ADSCs in our SVF pellets was > 6 × 105/ml of adipose tissue, which has the potential for differentiating into osteoblasts, adipocytes, and chondrocytes. Freshly collected adipose tissue is better for SVF isolation, and isolated SVF should also be kept at 4 °C and used as soon as possible. SVF may promote revascularization after fat grafting. The adipose tissue of an SVF co-transplanted group had an integral structure, clear capillaries, and higher VEGF expression. SVF co-transplantation inhibited adipose cell apoptosis.

CONCLUSION

Our study provides an efficient procedure for SVF isolation, its application in fat grafting, and possible underlying mechanisms.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Nanofat and Platelet-Rich Plasma injections used in a case of severe acne scars

BACKGROUND

Acne is a common chronic inflammatory disease, which can result in permanent scarring. Different types of treatments have been used in order to treat acne scars. However, esthetic results have proved variable. Furthermore, none of these treatments has had an impact on the underlying inflammatory process.

OBJECTIVE

The main purpose of this case-report is to suggest a new potential therapy for acne scar management combining esthetic filling with an anti-inflammatory and a regenerative action.

METHODS

A Platelet rich plasma (PRP) and Nanofat mixture was injected into the pathological dermis in order to treat and fill severe acne scars.

RESULTS

After a one- year follow-up, skin elasticity had improved, scar reduction and a reversal of the inflammation process had been observed.

CONCLUSIONS

PRP and Nanofat could represent a new and promising therapeutic approach in the treatment of the inflammatory scarring process in severe acne.

Modified nanofat grafting: Stromal vascular fraction simple and efficient mechanical isolation technique and perspectives in clinical recellularization applications

Background: Nanofat grafting (NG) is a simple and cost-effective method of lipoaspirates with inter-syringe passages, to produce stromal vascular fraction (SVF) and isolate adipose-derived stem cells (ASCs). This represents a tremendous interest in the future clinical needs of tissue engineering. In this study, we optimized the NG technique to increase the yield of ASC extractions.

Methods: We analyzed three groups of SVF obtained by 20, 30, and 40 inter-syringe passages. The control group was an SVF obtained by enzymatic digestion with Celase. We studied their cell composition by flow cytometry, observed their architecture by confocal microscopy, and observed immunomodulatory properties of the ASCs from each of the SVFs by measuring inflammatory markers of macrophages obtained by an ASC monocyte co-culture.

Results: We have established the first cell mapping of the stromal vascular fraction of adipose tissue. The results showed that SVF obtained by 20 inter-syringe passages contains more statistically significant total cells, more cells expressing the ASC phenotype, more endothelial cells, and produces more CFU-F than the SVF obtained by 30 and 40 passages and by enzymatic digestion. Confocal microscopy showed the presence of residual adipocytes in SVF obtained by inter-syringe passages but not by enzymatic digestion. The functional study indicates an orientation toward a more anti-inflammatory profile and homogenization of their immunomodulatory properties.

Conclusion: This study places mechanically dissociated SVF in the center of approaches to easily extract ASCs and a wide variety and number of other progenitor cells, immediately available in a clinical setting to provide both the amount and quality of cells required for decellularized tissues.

Regulation of Adipose Progenitor Cell Expansion in a Novel Micro-Physiological Model of Human Adipose Tissue Mimicking Fibrotic and Pro-Inflammatory Microenvironments

The expansion of adipose progenitor cells (APCs) plays an important role in the regeneration of the adipose tissue in physiological and pathological situations. The major role of CD26-expressing APCs in the generation of adipocytes has recently been highlighted, revealing that the CD26 APC subtype displays features of multipotent stem cells, giving rise to CD54- and CD142-expressing preadipocytes. However, a relevant human in vitro model to explore the regulation of the APC subpopulation expansion in lean and obese adipose tissue microenvironments is still lacking. In this work, we describe a novel adipose tissue model, named ExAdEx, that can be obtained from cosmetic surgery wastes. ExAdEx products are adipose tissue units maintaining the characteristics and organization of adipose tissue as it presents in vivo. The model was viable and metabolically active for up to two months and could adopt a pathological-like phenotype. The results revealed that inflammatory and fibrotic microenvironments differentially regulated the expansion of the CD26 APC subpopulation and its CD54 and CD142 APC progenies. The approach used significantly improves the method of generating adipose tissue models, and ExAdEx constitutes a relevant model that could be used to identify pathways promoting the expansion of APCs in physiological and pathological microenvironments.

Research Progress on Preparation, Mechanism, and Clinical Application of Nanofat

Autologous adipose tissue is an ideal soft tissue filling material in theory, which has the advantages of easy access, comprehensive source, and high biocompatibility and is now widely used in clinical practice. Based on the above benefits of autologous fat, autologous fat grafting is an essential technique in plastic surgery. Conventional macrofat is used to improve structural changes after soft tissue damage or loss caused by various causes such as disease, trauma, or aging. Due to the large diameter of particles and to avoid serious complications such as fat embolism, blunt needles with larger diameters (2 mm) are required, making the macrofat grafting difficult to the deep dermis and subdermis. Nanofat grafting is a relatively new technology that has gained popularity in cosmetic surgery in recent years. Nanofat is produced by mechanical shuffling and filtration of microfat, which is harvested by liposuction. The harvesting and processing of nanofat are cost-effective as it does not require additional equipment or culture time. Unlike microfat, nanofat particles are too small to provide a notable volumizing effect. Studies have shown that nanofat contains abundant stromal vascular fraction cells and adipose-derived stem cells, which help reconstruct dermal support structures, such as collagen, and regenerate healthier, younger-looking skin. Moreover, the fluid consistency of nanofat allows application in tissue regeneration, such as scars, chronic wounds, and facial rejuvenation. This article reviews the current research progress on the preparation, mechanism, and clinical application of nanofat.

Application of nanofat for treatment of traumatic faecal incontinence after sphincteroplasty - A pilot study

AIM

The aim of this study was to investigate whether the application of nanofat containing stem cells improves continence in women who had previously undergone anal sphincteroplasty with unsatisfactory long-term outcomes.

METHOD

This prospective pilot study included nine women with various degrees of anal incontinence who had previously undergone anal sphincteroplasty due to obstetric trauma. In all patients, the Wexner Incontinence Score (WS) and Faecal Incontinence Quality of Life Score (FIQLS), as well as anal manometry and endoanal ultrasound measurements, were performed before the procedure and during follow-up. In all patients, liposuction was performed and 50 ml of raw lipoaspirate was obtained and processed using a NanoFat Kit device. Approximately 20 ml of the mechanically emulsified and filtrated fat was obtained and the anal sphincter complex was infiltrated with it. Patient follow-up was conducted in person or via telephone 6 and 12 months after the procedure.

RESULTS

The squeeze pressure was significantly increased 6 months after the procedure (p = 0.01). The external anal sphincter measured at the 12 o'clock position was significantly thicker (p = 0.04). A significant decrease in the WS was observed both 6 and 12 months after the procedure compared with baseline values (p < 0.05 for both).

CONCLUSION

This study is the first to show that the application of nanofat as an injectable product improves continence in patients with unsatisfactory results after sphincteroplasty, suggesting it to be a promising and effective therapeutic tool. The procedure is safe and can be easily performed as an ambulatory procedure.

Engineering hypertrophic cartilage grafts from lipoaspirate for critical-sized calvarial bone defect reconstruction: An adipose tissue-based developmental engineering approach

Developmental engineering of living implants from different cell sources capable of stimulating bone regeneration by recapitulating endochondral ossification (ECO) is a promising strategy for large bone defect reconstruction. However, the clinical translation of these cell-based approaches is hampered by complex manufacturing procedures, poor cell differentiation potential, and limited predictive in vivo performance. We developed an adipose tissue-based developmental engineering approach to overcome these hurdles using hypertrophic cartilaginous (HyC) constructs engineered from lipoaspirate to repair large bone defects. The engineered HyC constructs were implanted into 4-mm calvarial defects in nude rats and compared with decellularized bone matrix (DBM) grafts. The DBM grafts induced neo-bone formation via the recruitment of host cells, while the HyC pellets supported bone regeneration via ECO, as evidenced by the presence of remaining cartilage analog and human NuMA-positive cells within the newly formed bone. However, the HyC pellets clearly showed superior regenerative capacity compared with that of the DBM grafts, yielding more new bone formation, higher blood vessel density, and better integration with adjacent native bone. We speculate that this effect arises from vascular endothelial growth factor and bone morphogenetic protein-2 secretion and mineral deposition in the HyC pellets before implantation, promoting increased vascularization and bone formation upon implantation. The results of this study demonstrate that adipose-derived HyC constructs can effectively heal large bone defects and present a translatable therapeutic option for bone defect repair.

Adipose stromal vascular fraction: a promising treatment for severe burn injury

Thermal skin burn injury affects both adults and children globally. Severe burn injury affects a patient's life psychologically, cosmetically, and socially. The pathophysiology of burn injury is well known. Due to the complexity of burn pathophysiology, the development of specific treatment aiding in tissue regeneration is required. Treatment of burn injury depends on burn severity, size of the burn and availability of donor site. Burn healing requires biochemical and cellular events to ensure better cell response to biochemical signals of the healing process. This led to the consideration of using cell therapy for severe burn injury. Adult mesenchymal stem cells have become a therapeutic option because of their ability for self-renewal and differentiation. Adipose stromal vascular fraction (SVF), isolated from adipose tissues, is a heterogeneous cell population that contains adipose-derived stromal/stem cells (ADSC), stromal, endothelial, hematopoietic and pericytic lineages. SVF isolation has advantages over other types of cells; such as heterogeneity of cells, lower invasive extraction procedure, high yield of cells, and fast and easy isolation. Therefore, SVF has many characteristics that enable them to be a therapeutic option for burn treatment. Studies have been conducted mostly in animal models to investigate their therapeutic potential for burn injury. They can be used alone or in combination with other treatment options. Treatment with both ADSCs and/or SVF enhances burn healing through increasing re-epithelization, angiogenesis and decreasing inflammation and scar formation. Research needs to be conducted for a better understanding of the SVF mechanism in burn healing and to optimize current techniques for enhanced treatment outcomes.

Protein profiling of mechanically processed lipoaspirates: discovering wound healing and anti-fibrotic biomarkers in nanofat

BACKGROUND

Nanofat is an injectable oily emulsion, rich in adipose derived stem cells (ADSCs) and growth factors. It is prepared from lipoaspirates through mechanical emulsification and filtration. Despite being successfully used in several procedures in regenerative medicine such as scar attenuation, skin rejuvenation and treatment of chronic wounds, little is known about exactly how nanofat induces regeneration in treated skin at the molecular level.

METHODS

Microfat and nanofat samples were isolated from 18 healthy patients. Proteomic profiling was performed through untargeted mass spectrometry proteomics and multiplex antibody arrays. Pathway enrichment analysis of differentially expressed proteins between microfat and nanofat was performed using Gene Ontology, Reactome and KEGG as reference databases.

RESULTS

Untargeted proteomics showed that upregulated genes in nanofat are involved in innate immunity responses, coagulation and wound healing, while downregulated genes were linked to cellular migration and extracellular matrix (ECM) production. Secretome array screening of microfat and nanofat samples showed no significantly different expression, which strongly suggests that the mechanical emulsification step does not affect the concentration of tissue regeneration biomarkers. The identified proteins are involved in wound healing, cellular migration, extracellular matrix remodelling, angiogenesis, stress response and immune response.

CONCLUSIONS

Mechanical processing of lipoaspirates into nanofat significantly influences the proteome profile by enhancing inflammation, antimicrobial and wound healing pathways. Nanofat is extremely rich in tissue repair and tissue remodelling factors.

CLINICAL RELEVANCE STATEMENT

This study shows that the effects of Micro- and Nanofat treatment are based on upregulated inflammation, antimicrobial and wound healing pathways. Mechanical emulsification does not alter the concentration of tissue regeneration biomarkers.

Improved symptoms and signs of refractory interstitial cystitis in women after intravesical Nanofat plus platelet-rich plasma grafting: A pilot study

Interstitial cystitis/bladder pain syndrome (IC/BPS) is characterized by bladder pain accompanied by irritative urinary symptoms, and typical cystoscopic and histological features. In this pilot study, we assessed the impact of lesion-targeted bladder injection therapy using a biocellular regenerative medicine on patients with refractory IC/BPS. The medicine, which was an autologous emulsified fat (Nanofat) and platelet-rich plasma (PRP) combination, was prepared intraoperatively. Six patients (aged 40-54 years), who completed a standard protocol of four consecutive treatments at 3-month intervals, were followed up at 6 months postoperatively. All patients (100%) reported marked (+3; +3 ~ -3) improvement of their overall bladder conditions. Mean bladder pain (from 8.2 to 1.7; range: 0 ~ 10), IC-related symptoms (from 18.5 to 5.7; range: 0 ~ 20), and bother (from 14.8 to 3.8; range: 0 ~ 16) improved significantly (p < 0.01). The normalization of bladder mucosal morphology with treatments was remarkable under cystoscopic examination, and no significant adverse events were found. The cultured mesenchymal stem cells from Nanofat samples of the six patients were verified in vitro. Our preliminary results suggest novel intravesical therapy with autologous Nanofat plus PRP grafting is safe and effective for refractory IC/BPS. Surgical efficacy might be attributed to an in vivo tissue engineering process.

Experimental study on the influence of different aperture connectors on nanofat

BACKGROUND

Nanofat, as a derivative of adipose tissue, has gradually become a research hotspot in beauty and regenerative medicine. However, the nanofat preparation method has not yet been standardized; it remains unknown whether the aperture of the connector has any influence on the transplantation effect.

METHODS

Adipose tissue was mechanically emulsified into nanofat tissue through different connector apertures (1.0, 1.5, and 2.0 mm). Cell survival and apoptosis were measured using the volume of oil droplets, glucose transportation test, flow cytometry, cell counting kit-8 (CCK-8), wound healing assay, transwell migration assay, and fluorescence staining. The expression of adiponectin, GluT4, and PPAR-γ in nanofat-derived stem cells (NFSCs) was detected using quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

The fineness of nanofat tissue texture decreased with an increase in the aperture connector. The amounts of glucose transferred in the three groups (1, 1.5, and 2 mm) were 4.7 ± 0.894, 6.1 ± 1.026, and 6.9 ± 0.868 mmol/L, respectively. Flow cytometric analysis showed that the proportion of NFSCs in the 2.0 mm group was the highest (91.267±1.210%). Cell proliferation and migration abilities were stronger in the 1.5 and 2.0 mm groups. The numbers of late apoptotic and dead cells in the 2.0 mm group were significantly fewer than those in the two other groups. Expression levels of lipid-related genes were as follows: adiponectin > GluT4 > PPAR-γ in each component.

CONCLUSIONS

As nanofat is emulsified, the use of larger aperture connectors (2.0 mm) appeared to decrease the degree of adipocyte lysis and increase the biological activity of adipose tissue.

Nanofat functionalized injectable super-lubricating microfluidic microspheres for treatment of osteoarthritis

Nanofat (NF) is a fine emulsion that has been used to treat a variety of diseases given its abundance of bioactive components. However, the biological functions of NF have been limited due to its inability to localize during implantation. In this study, NF was immobilized in microfluidic-generated aldehyde-modified polylactic glycolic acid (PLGA) porous microspheres (PMs) via Schiff base condensation and non-covalent binding in a three-dimensional (3D) porous network (PMs@NF). The PMs effectively enhanced the cartilage-targeted retention efficiency of NF, which also resulted in remarkable lubrication performance, with the friction coefficient being reduced by ∼80%, which was maintained over time. Meanwhile, the 3D penetrating structure of the microspheres stimulated cytokine secretion by the NF-derived stem cells, upregulating the expression of anabolism-related genes and downregulating catabolism, and the expression of inflammation-related and pain-related genes. Injecting PMs@NF into the knee joint cavity of a rat model with destabilization of the medial meniscus (DMM) reduced osteophyte formation and protected the cartilage from degeneration, thereby inhibiting the progression of osteoarthritis and improving animal behavior. In summary, this study developed a multifunctional platform with NF immobilization and super-lubrication, which showed great potential for the minimally invasive treatment of osteoarthritis.

Adipose Collagen Fragment: A Novel Adipose-Derived Extracellular Matrix Concentrate for Skin Filling

BACKGROUND

Skin filler is an option for treating skin aging and wrinkles; however, currently used fillers are limited by poor biocompatibility, rapid degradation, and possible hypersensitivity reactions. Autologous adipose tissue-derived products have been recognized as promising options for skin rejuvenation.

OBJECTIVES

This study aimed to develop a novel adipose-derived product for skin filling.

METHODS

Adipose collagen fragment (ACF) was prepared through pulverization, filtration, and centrifugation. The macrography, structure, types of collagen, and cell viability of ACF were evaluated by immunostaining, western blotting, and cell culture assays. ACF, nanofat, and phosphate-buffered saline (9 spots/side, 0.01 mL/spot) were intradermally injected in the dorsal skin of 36 female BALB/c nude mice; the skin filling capacity and the collagen remodeling process were then investigated. Twenty-one female patients with fine rhytides in the infraorbital areas were enrolled and received clinical applications of ACF treatment. Therapeutic effects and patients' satisfaction scores were recorded.

RESULTS

The mean [standard deviation] yield of ACF from 50 mL of Coleman fat was 4.91 [0.25] mL. ACF contained nonviable cells and high levels of collagen I, collagen IV, and laminin. Fibroblasts and procollagen significantly increased in ACF and ACF-treated dermis (P < 0.05). Overall, 85.7% of patients were satisfied with the therapy results, and no infections, injection site nodules, or other unwanted side effects were observed.

CONCLUSIONS

ACF significantly improved dermal thickness and collagen synthesis and may serve as a potential autologous skin filler.

Cell-Free Extracts from Human Fat Tissue with a Hyaluronan-Based Hydrogel Attenuate Inflammation in a Spinal Cord Injury Model through M2 Microglia/Microphage Polarization

Treatment for spinal cord injuries (SCIs) is often ineffective because SCIs result in a loss of nerve tissue, glial scar formation, local ischemia and secondary inflammation. The current promising strategy for SCI is the combination of bioactive materials and cytokines. Bioactive materials support the injured spinal cord, stabilize the morphology, and avoid excessive inflammatory responses. Fat extract (FE) is a cell-free liquid component containing a variety of cytokines extracted from human fat tissue using mechanical methods. In this research, a biocompatible HAMC (hyaluronan and methylcellulose) loaded with FE is used to treat a model of spinal cord contusion in mice. The composite not only inhibits death of neuro- and vascular cells and leads to the preservation of neural and vascular structure, but also modulates the inflammatory phenotype of macrophages in the locally injured region. Specifically, FE promotes the polarization of macrophages from an inflammatory M1 phenotype to an anti-inflammatory M2 phenotype. During the screening of the involved pathways, it is corroborated that activation of the STAT6/Arg-1 signaling pathway is involved in macrophage M2 polarization. In summary, FE is a promising treatment for SCI, as it is easy to obtain, nonimmunogenic, and effective.

Treatment of scars with autologous fat grafting and 1540 nm non-ablative erbium laser

Scars may be devastating for patients. Fat grafting and non-ablative lasers are available options for improvement. The former reshapes and improves scar quality by adding volume and regenerative adipose-derived stem cells, whereas the latter facilitates synthesis and deposition of new dermal collagen. The combination may be synergic, leading to better cosmetic outcome.This was a prospective study of 16 consecutive patients treated with autologous fat grafting and non-ablative 1540-nm erbium laser for facial scars between January 2015 and December 2015. Treatment protocol included fat injection followed by five treatments with 1540-nm erbium laser (ICON^TM Cynosure; Westford, MA, USA) a month later. We evaluated patients before, after treatments, and 6 months after the final treatment.Sixteen patients participated in our study. Mean patient age was 42 years (range 16-59 years). Scars were either traumatic (73%) or acne induced (27%). Traumatic scars were mainly new scars, with the majority of patients were treated within 30 days of injury. There were no reported complications. Scars improved in both texture and appearance and patient satisfaction was high in all cases.Treatment of scars with autologous fat grafting and fractional non-ablative 1540-nm erbium laser is safe and efficient and results in improved scar appearance and texture.

Low Negative Pressure Combined With Supertumescence Microliposuction as a New Method for Repairing Facial Fat Overfilling: A Case Series of 32 Patients

BACKGROUND

Face fat overfilling sometimes occurs and is unfortunately very difficult to repair.

OBJECTIVES

The aim of this study was to report initial experience of microliposuction with low negative pressure combined with supertumescence (LNPST) in a case series of 32 patients.

METHODS

The LNPST microliposuction was performed in 32 patients aged 22 to 41 years (mean [standard deviation] age, 29.6 [4.9] years) with facial overfilling. Discomfort and bleeding were monitored intraoperatively by 2 independent plastic surgeons, who used a grading system to record the results. All patients were followed-up for hematoma within 1 week postoperatively and for skin numbness and muscle paralysis at 1 week and 3 months postoperatively. In addition, at 6 months postoperatively, patient satisfaction with the postoperative aesthetic effects was analyzed by FACE-Q questionnaire.

RESULTS

All patients successfully completed the operation under local anesthesia. The mean intraoperative discomfort and blood-loss scores were 1.69 [0.62] and 1.22 [0.41], respectively. The hematoma score was 1.13 [0.34] within 1 week. Other scores included postoperative skin numbness (1 week, 1.96 [0.62]; 3 months, 1.13 [0.33]) and postoperative muscle paralysis (1 week, 1.22 [0.51]; 3 months, 1.0 [0]). Overall, neither skin necrosis nor serious complications requiring revision surgery occurred. Seventy-two percent of the patients (n = 23) answered the FACE-Q questionnaire and the score was 21.8 (1.7), covering satisfaction with the outcome score into a standard score (81.7 [15.1], from 0 to 100), which verified the high satisfaction rate.

CONCLUSIONS

LNPST technology is a safe and effective method for repair of facial fat overfilling, with less bleeding, less nerve injury, fewer complications, and high patient satisfaction.

LEVEL OF EVIDENCE: 4

Fat obtained from plastic surgery procedures—stem cells derived from adipose tissue and their potential in technological innovation: a narrative literature review and perspective on dissociative methods

Background

Throughout its illustrious history, plastic surgery has searched for novel regenerative therapies and procedures. Recently, interest has emerged in using adipose tissue-derived stem cells (ASCs) in an ethical, easy, and reproducible manner. ASCs are generally not administered alone but as a constituent of the stromal vascular fraction (SVF) in clinical practice. Herein, we searched for innovative fat collection and ASC isolation technologies and applications and evaluated each study’s relevance to plastic surgery.

Methods

A narrative literature review was carried out using the MEDLINE/PubMed databases. Studies published from January 1993 to August 2020 and written in English, Portuguese, or Spanish were considered.

Results

The selection process yielded 33 articles for subsequent review, involving exploratory, selective, and interpretive reading, material choice, and text analysis. Twenty-three articles employed enzymatic dissociation methods to isolate ASCs, and 25 employed liposuction as the plastic surgery technique. Moreover, articles describing new devices (n = 2), techniques (n = 4), computational models (n = 1), tissue scaffolds (n = 21), and therapies and/or treatments (n = 5) were identified.

Conclusions

Given the importance of fat tissue for plastic surgery purposes, innovative ASC isolation and liposuction technologies could change how the surgeon conducts surgeries and improve surgical outcomes. Furthermore, many articles investigating tissue scaffolds demonstrate the importance of this area of research and development in plastic surgery and regenerative medicine. Continued efforts in the identified research areas will eventually bring in vivo human plastic surgery applications and regenerative medicine into the operating room. Level of evidence: Not gradable.

Enrichment of Nanofiber Hydrogel Composite with Fractionated Fat Promotes Regenerative Macrophage Polarization and Vascularization for Soft-Tissue Engineering

BACKGROUND

Fractionated fat has been shown to promote dermal regeneration; however, the use of fat grafting for reconstruction of soft-tissue defects is limited because of volume loss over time. The authors have developed a novel approach for engineering of vascularized soft tissue using an injectable nanofiber hydrogel composite enriched with fractionated fat.

METHODS

Fractionated fat was generated by emulsification of groin fat pads from rats and mixed in a 3:1 ratio with nanofiber hydrogel composite (nanofiber hydrogel composite with fractionated fat). Nanofiber hydrogel composite with fractionated fat or nanofiber hydrogel composite alone was placed into isolation chambers together with arteriovenous loops, which were subcutaneously implanted into the groin of rats (n = 8 per group). After 21 days, animals were euthanized and systemically perfused with ink, and tissue was explanted for histologic analysis. Immunofluorescent staining and confocal laser scanning microscopy were used to quantify CD34+ progenitor cell and macrophage subpopulations.

RESULTS

Nanofiber hydrogel composite with fractionated fat tissue maintained its shape without shrinking and showed a significantly stronger functional vascularization compared to composite alone after 21 days of implantation (mean vessel count, 833.5 ± 206.1 versus 296.5 ± 114.1; p = 0.04). Tissue heterogeneity and cell count were greater in composite with fractionated fat (mean cell count, 49,707 ± 18,491 versus 9263 ± 3790; p = 0.005), with a significantly higher number of progenitor cells and regenerative CD163+ macrophages compared to composite alone.

CONCLUSIONS

Fractionated fat-enriched nanofiber hydrogel composite transforms into highly vascularized soft tissue over 21 days without signs of shrinking and promotes macrophage polarization toward regenerative phenotypes. Enrichment of injectable nanofiber hydrogel composite with fractionated fat represents a promising approach for durable reconstruction of soft-tissue defects.

CLINICAL RELEVANCE STATEMENT

The authors' approach for tissue engineering may ultimately lay the groundwork for clinically relevant applications with the goal of generating large volumes of vascularized soft tissue for defect reconstruction without donor site morbidity.

Research update of adipose tissue-based therapies in regenerative dermatology

Mesenchymal stromal/stem cells (MSCs) have a spontaneous propensity to support tissue homeostasis and regeneration. Among the several sources of MSCs, adipose-derived tissue stem cells (ADSCs) have received major interest due to the higher mesenchymal stem cells concentration, ease, and safety of access. However, since a significant part of the natural capacity of ADSCs to repair damaged tissue is ascribable to their secretory activity that combines mitogenic factors, cytokines, chemokines, lipids, and extracellular matrix components, several studies focused on cell-free strategies. Furthermore, adipose cell-free derivatives are becoming more attractive especially for non-volumizing purposes, such as most dermatological conditions. However, when keratinocytes, fibroblasts, melanocytes, adipocytes, and hair follicle cells might not be locally sourced, graft of materials containing concentrated ADSCs is preferred. The usage of extracellular elements of adipose tissue aims to promote a self-autonomous regenerative microenvironment in the receiving area restoring physiological homeostasis. Hence, ADSCs or their paracrine activity are currently being studied in several dermatological settings including wound healing, skin fibrosis, burn, and aging.The present work analyzing both preclinical and clinical experiences gives an overview of the efficacy of adipose tissue-derivatives like autologous fat, the stromal vascular fraction (SVF), purified ADSCs, secretome and extracellular matrix graft in the field of regenerative medicine for the skin.

In Vivo Evaluation of Mechanically Processed Stromal Vascular Fraction in a Chamber Vascularized by an Arteriovenous Shunt

Mechanically processed stromal vascular fraction (mSVF) is a promising source for regenerative purposes. To study the in vivo fate of the mSVF, we herein used a vascularized tissue engineering chamber that insulates the target mSVF from the surrounding environment. In contrast to previous models, we propose an arteriovenous (AV) shunt between saphenous vessels in rats without a venous graft. Mechanical SVF was processed from the fat pads of male Sprague Dawley rats, mixed with a fibrin hydrogel and implanted into an inguinal tissue engineering chamber. An arteriovenous shunt was established between saphenous artery and vein. On the contralateral side, an mSVF-fibrin hydrogel mix without vascular axis served as a non-vascularized control. After two and six weeks, rats were sacrificed for further analysis. Mechanical SVF showed significant numbers of mesenchymal stromal cells. Vascularized mSVF explants gained weight over time. Perilipin and CD31 expression were significantly higher in the mSVF explants after six weeks while no difference in DAPI positive cells, collagen deposition and FABP4 expression was observed. Morphologically, no differentiated adipocytes but a dense cell-rich tissue with perilipin-positive cells was found after six weeks. The phosphorylation of ERK1/2 was significantly enhanced after six weeks while Akt activation remained unaltered. Finally, mSVF explants stably expressed and released VEGF, bFGF and TGFb. Vascularized mSVF is able to proliferate and express adipocyte-specific markers. The AV shunt model is a valuable refinement of currently existing AV loop models in the rat which contributes to the fundamental 3R principles of animal research.

Boosting Tissue Vascularization: Nanofat as a Potential Source of Functional Microvessel Segments

Nanofat is increasingly applied in plastic surgery for the improvement of scar quality and skin rejuvenation. However, little is known about the underlying regenerative mechanisms. Therefore, we herein investigated nanofat grafts in a murine dorsal skinfold chamber model. Nanofat generated from subcutaneous, inguinal adipose tissue of green fluorescent protein (GFP)+ C57BL/6 male and female donor mice was injected intracutaneously into dorsal skinfold chambers of gender-matched GFP− wild-type mice. The vascularization and tissue composition of the grafted nanofat were analyzed by means of intravital fluorescence microscopy, histology and immunohistochemistry over an observation period of 14 days. The freshly generated nanofat consisted of small fragments of perilipin+ adipocytes surrounded by Sirius red+ collagen fibers and still contained intact CD31+/GFP+ vessel segments. After transplantation into the dorsal skinfold chamber, these vessel segments survived and developed interconnections to the surrounding CD31+/GFP− host microvasculature. Accordingly, the grafted nanofat rapidly vascularized and formed new microvascular networks with a high functional microvessel density on day 14 without marked differences between male and female mice. Even though further research is needed to confirm these findings, the present study suggests that nanofat boosts tissue vascularization. Thus, nanofat may represent a versatile resource for many applications in tissue engineering and regenerative medicine.

Oral and Maxillofacial Autologous Fat Transplantation: History, Clinical Application Status and Research Progress

After more than a century of development, autologous fat transplantation (AFT), a repair method for soft tissue defects and deformities, has the advantages of being simple, rapid, effective and safe, and it is increasingly favoured by plastic surgeons. This article reviews the developmental history of AFT, analyses its clinical application status in the oral and maxillofacial regions, and provides a preliminary summary and discussion of the research progress related to AFT. The hope is that that this technique could be widely applied for oral and maxillofacial diseases as well as facial rejuvenation indications. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Adipose-Derived Stem Cells for Facial Rejuvenation

The interest in regenerative medicine is increasing, and it is a dynamically developing branch of aesthetic surgery. Biocompatible and autologous-derived products such as platelet-rich plasma or adult mesenchymal stem cells are often used for aesthetic purposes. Their application originates from wound healing and orthopaedics. Adipose-derived stem cells are a powerful agent in skin rejuvenation. They secrete growth factors and anti-inflammatory cytokines, stimulate tissue regeneration by promoting the secretion of extracellular proteins and secrete antioxidants that neutralize free radicals. In an office procedure, without cell incubation and counting, the obtained product is stromal vascular fraction, which consists of not only stem cells but also other numerous active cells such as pericytes, preadipocytes, immune cells, and extra-cellular matrix. Adipose-derived stem cells, when injected into dermis, improved skin density and overall skin appearance, and increased skin hydration and number of capillary vessels. The main limitation of mesenchymal stem cell transfers is the survival of the graft. The final outcomes are dependent on many factors, including the age of the patient, technique of fat tissue harvesting, technique of lipoaspirate preparation, and technique of fat graft injection. It is very difficult to compare available studies because of the differences and multitude of techniques used. Fat harvesting is associated with potentially life-threatening complications, such as massive bleeding, embolism, or clots. However, most of the side effects are mild and transient: primarily hematomas, oedema, and mild pain. Mesenchymal stem cells that do not proliferate when injected into dermis promote neoangiogenesis, that is why respectful caution should be taken in the case of oncologic patients. A longer clinical observation on a higher number of participants should be performed to develop reliable indications and guidelines for transferring ADSCs.

Histological analysis of the effect of nanofat grafting in scar rejuvenation

Introduction:

Aims:

Materials and Methods:

Results:

Conclusion:

Fat injection and its clinical applications

Fat injection has been in application for more than two decades, and its usefulness has been well documented. In our article, we want to highlight the various applications and usefulness of this versatile technique. We also want to showcase the methods to ensure good results and maximize the uptake of fat grafts with minimal absorption. Our results in our series of 110 consecutive cases have been very encouraging, with excellent patient satisfaction.

Indication-based protocols with different solutions for mechanical stromal-cell transfer

Background

Regenerative medicine is the fastest developing branch of plastic surgery in recent times. Adipose tissue is one of the largest and most important sources in the body for stromal cells. Although mechanical isolation methods are both very popular and have many advantages, they still have no accepted protocols.

Objective

We developed new protocols called indication-based protocols (IPs) for standardization and new techniques called mechanical stromal-cell transfer (MEST) by using ultra-sharp blades and dilution of adipose tissue with different solutions (saline, Ringer and 5% Dextrose)

Methods & material: In order to obtain the desired physical structure (liquid, gel, solid) and the desired volume, four different types of IPs have been defined. Adipose tissue was prediluted with different solutions using 10 or 20 cc injectors in IPs 1 and 2, while condensed adipose tissue was used directly in IPs 3 and 4.

Results

In MEST, stromal cells were obtained from 100 mL of condensed fat using different IPs with 92% mean viability and cell counts of 26.80–91.90 × 10⁶. Stromal cells can be obtained in the desired form and number of cells by using four different IPs.

Conclusion

Isolation of stromal cells by cutting fat with sharp blades will prevent the death of fat tissue and stromal cells and will allow high viability and cell count with our new technique. Predilution with different solutions: Diluting the condensed adipose tissue with the desired solutions (saline, Ringer or 5% Dextrose) before the adinizing process will provide even more stromal cells.

Lay Summary

Obtaining regenerative stromal cells from adipose tissue can be done by two methods: Enzymatic and mechanical. Mechanical methods have many advantages. Although mechanical stromal cell extraction from adipose tissue is very popular and many techniques have been described, there are still no accepted protocols, definition for the end product, and no consensus on the status of the stromal cells. In this study, stromal cells were obtained mechanically by using ultra-sharp blade systems, without exposing adipose tissue to blunt trauma. Thus, a higher number of cells and higher viability could be obtained. An “Indication based” protocol has been defined for the first time in order to obtain the desired number and status (solid, semi-solid, liquid)

end product. Diluting the condensed adipose tissue with the desired solutions (saline, Ringer or 5% Dextrose) before the adinizing process will provide even more stromal cells. This will provide an opportunity for clinicians to obtain and apply a stromal cell solution for different indications in different anatomical regions.

Combining systemic and locally applied cellular therapies for the treatment of systemic sclerosis

Systemic sclerosis (SSc) is a complex autoimmune disease characterized by a functional and structural alteration of the microvascular network associated with cutaneous and visceral fibrosis lesions. Conventional therapies are based on the use of immunomodulatory molecules and symptomatic management but often prove to be insufficient, particularly for patients suffering from severe and rapidly progressive forms of the disease. In this context, cellular therapy approaches could represent a credible solution with the goal to act on the different components of the disease: the immune system, the vascular system and the extracellular matrix. The purpose of this review is to provide an overview of the cellular therapies available for the management of SSc. The first part will focus on systemically injected therapies, whose primary effect is based on immunomodulatory properties and immune system resetting, including autologous hematopoietic stem cell transplantation and intravenous injection of mesenchymal stem cells. The second part will discuss locally administered regenerative cell therapies, mainly derived from adipose tissue, developed for the management of local complications as hand and face disabilities.